The thermal energy contained in exhaust gases represents about 30% of the energy contained in the fuel. A heat recovery device is intended to transfer this energy to another fluid, such as an engine coolant or oil.
Already known in the state of the art, in particular according to FR 3,031,140, is a heat recovery device for an exhaust line, extending between an exhaust gas inlet and outlet, and including a valve defining a gas passage toward the exhaust gas outlet. The device houses a gate that is movable around a pivot link between a closing off position and a free position of the passage. The device further includes a heat exchanger comprising an exchanger inlet communicating with the valve upstream from the gate, and an exchanger outlet communicating with the valve downstream from the gate.
The heat exchanger is intended to allow the exchange of heat between the exhaust gases, passing through this heat exchanger, and a heat transfer fluid, in particular a coolant.
When the gate is in the closing off position, the circulation of the exhaust gases is forced from the inlet toward the gas outlet through the heat exchanger. When the gate is in the free position, the exhaust gases circulate through the passage defined by the valve, the exchanger then being inactive.
In such a device, the gate bears against a seat formed by a flat shell arranged in the valve.
This shell is welded in the valve, such that there is a risk of this shell deforming under the effect of the heat given off by the welding. In this case, the tightness between the shell and the valve in the closing off position is sometimes not correctly provided.
Also known in the state of the art, in particular according to JP 2016 044 666 A, is a heat recovery device in which the seat for the gate is supported by a conical shell, the gate then having a complementary conical shape. The conical shell is also welded in the valve.
Tightness is also difficult to provide in this device, since the conical shell also risks being deformed when it is welded in the valve, and the shape of the gate is difficult to obtain. The shape is also potentially subject to deformation during the design of the gate. Yet any deformation of the shell or gate modifies the relative position of the shell and this gate, which then results in leaks.